CN112135891A

CN112135891A - A turbomachinery chemical reactor and a method for cracking hydrocarbons in a process fluid

Info

Publication number: CN112135891A
Application number: CN201880093457.8A
Authority: CN
Inventors: 西尔瓦诺·R·萨雷托; 保罗·莫里森·布朗; 柯克·瑞安·吕普克斯; 戴维·安德鲁·泰勒
Original assignee: Individual
Current assignee: Siemens Energy Global GmbH and Co KG; Siemens Energy Inc
Priority date: 2018-05-16
Filing date: 2018-05-16
Publication date: 2020-12-25
Anticipated expiration: 2038-05-16
Also published as: US11059018B2; FI3768801T3; US11278860B2; CN112135891B; EP3768801A1; US20210268469A1; WO2019221726A1; US20210069665A1; EP3768801B1; ES2966364T3

Abstract

A chemical reactor (10) and method crack hydrocarbons in a process fluid by: accelerating the process fluid to a velocity greater than mach 1 using an axially-propelling impeller (40); a shock wave (90) is generated in a process fluid by decelerating the process fluid in a static diffuser (70) having diverging diffuser passages (72). The temperature increase of the process fluid downstream of the shock wave cracks entrained hydrocarbons in a single pass through the unidirectional flow path (F) within a single stage without the need to recirculate the process fluid to otherwise pass through the same stage. In some embodiments, a turbomachinery chemical reactor (110) has one or more axially-impelling impellers (40A, 40B) of multiple successive stages paired with diverging passages of a static diffuser (70). The successive stages crack additional hydrocarbons by successively increasing the temperature of the flowing process fluid.

Description

A turbomachinery chemical reactor and a method for cracking hydrocarbons in a process fluid

Technical Field

The present invention relates to a chemical reactor and a method for cracking hydrocarbons in a process fluid. More particularly, the present invention relates to a turbomachinery chemical reactor and method for cracking hydrocarbons.

Background

Petroleum refineries and petrochemical plants fractionate or "crack" heavier Molecular Weight (MW) hydrocarbons. After cracking, lighter molecular weight hydrocarbons are used in the petrochemical industry as feedstocks for products of other compounds. In a known commercially practiced pyrolytic cracking process, MW heavier hydrocarbons are fractionated into various MW lighter olefins, such as ethylene, without causing combustion, under heat and pressure applied in a furnace-type chemical reactor in a low oxygen environment. Typically, the MW heavier hydrocarbons are entrained in the heated steam. The process fluid containing steam or containing hydrocarbons flows through the heat exchanger of the chemical reactor. The temperature and residence time of the process fluid being passed in the heat exchanger is controlled to crack entrained hydrocarbons to lower MW hydrocarbons of the desired output.

Using the example of ethylene production by pyrolysis, a process fluid comprising hydrocarbons and steam is heated from 1220 ° f to 1545 ° f in less than 400 Milliseconds (MS) in a furnace-type chemical reactor. The rate at which the heating is complete and then quenched (to stop further chemical reaction) is important to produce the desired mixture of hydrocarbons. Oxygen must not be present during the heating process to avoid hydrocarbon combustion. A large heat input and output and a relatively slow mass flow rate of the process fluid are required during the reaction in the furnace-type chemical reactor. To meet the output targets, ethylene production plants employ multiple parallel pyrolysis reactors, each requiring a large heat input. Each additional reactor required to meet the production target adds capital expenditure, energy consumption to heat the process fluid, plant real estate space.

It is desirable to increase the mass flow of process fluids during the hydrocarbon cracking process with lower production energy input. The increased mass flow meets production goals with less plant equipment capital expenditure and real estate space.

Disclosure of Invention

Exemplary embodiments of the chemical reactors and methods described herein crack hydrocarbons in a process fluid by: accelerating the process fluid to a velocity greater than mach 1 using an axially impelling impeller; and generating a shock wave in the process fluid by decelerating the process fluid in a static diffuser having an expanding diffuser channel. Cracking occurs in a single stage at a faster reaction rate and with less energy input than in conventional pyrolysis-type chemical reactors. The increased mass flow rate provided by embodiments of the present invention increases production with less plant equipment capital expenditure and lower energy usage compared to conventional pyrolysis-type chemical reactors and processes.

The housing of the turbomachinery chemical reactor described herein has an annular housing channel defining a unidirectional axial flow path from the housing inlet to the housing outlet. The rotating axially impelling impeller imparts energy to the process fluid and discharges the process fluid at a velocity greater than mach 1. A static annular diffuser having an expanding diffuser passage is located in the annular housing passage and is oriented between the axially advancing impeller and the outlet of the housing. The diffuser passage is configured to decelerate a process fluid in the diffuser passage discharged from blades of the impeller to a velocity less than mach 1. This deceleration creates a shock wave in the process fluid prior to discharging the process fluid from the outlet of the shell or to the next successive stage in the chemical reactor, thereby raising the temperature of the process fluid downstream of the shock wave sufficiently to crack hydrocarbons entrained with the process fluid. In some embodiments, a turbomachinery chemical reactor has one or more axially-impelling impellers of multiple successive stages paired with diverging passages of a static diffuser. Each chemical reactor stage cracks hydrocarbons in the process fluid in a single unidirectional flow path from its inlet to its outlet without recirculating the process fluid in the opposite direction to otherwise pass through the same stage. The unidirectional flow path promotes cracking in a relatively short annular flow path of large cross-sectional area. In some embodiments, hydrocarbons are cracked in a single stage with a higher mass flow rate in 10 milliseconds (10MS) or less. In some embodiments, successive stages in combination with a propelling impeller and a paired pair of expanding static diffusers crack additional hydrocarbons by successively raising the temperature of the process fluid in each stage.

Exemplary embodiments of the invention feature a chemical reactor for cracking hydrocarbons in a process fluid. The chemical reactor includes a housing having a housing inlet, a housing outlet, and an annular housing passage defining a unidirectional axial flow path from the housing inlet to the housing outlet for containing the process fluid and hydrocarbons in the cracked process fluid in the axial flow path. A rotating shaft located in the housing is surrounded by an annular housing channel for coupling to a shaft rotating power source, such as an electric motor or turbine engine. The rotating shaft defines a shaft center axis that is in a fixed orientation in the housing and that coincides with the axis of rotation of the rotating shaft. An axial impeller is mounted about the axis of rotation in an annular housing passage and is in fluid communication with the process fluid flowing between the inlet and outlet of the housing. The impeller has an impeller hub with an axial length extending axially along a shaft center axis of the rotating shaft. A row of a plurality of impeller blades project outwardly from the impeller hub. Each of the respective impeller blades has a leading edge facing the housing inlet, a trailing edge facing the housing outlet, blade tips in opposed spaced relation to the annular housing passage at a distal end of the impeller hub, and opposed concave and convex blade sidewalls between the blade tips and between the leading and trailing edges. The impeller blades are configured to transition the velocity of the process fluid tangentially relative to the shaft central axis from a first tangential direction at the leading edges of the blades to an opposite tangential direction at the trailing edges of the blades as the rotating shaft rotates, and impart energy into the process fluid to discharge the process fluid from the respective trailing edges of the impeller blades at a velocity greater than mach 1. A static annular diffuser is located in the annular housing passage and is oriented between the axially-propelling impeller and the outlet of the housing. The static annular diffuser has a plurality of radially oriented circumferentially spaced diffuser passages spanning a row of annular casing passages. Each of the respective diffuser passages has a first axial end facing the axially-propelling impeller and a second axial end facing the housing outlet. The local cross-section of each diffuser passage increases from its first axial end to its second axial end. The diffuser passage is configured to decelerate the process fluid discharged from the impeller blades in the diffuser passage to a velocity less than Mach 1. This deceleration creates a shock wave in the process fluid prior to discharging the process fluid from the housing outlet, raising the temperature of the process fluid downstream of the shock wave.

Other exemplary embodiments of the invention feature methods for cracking hydrocarbons in a process fluid. The exemplary method is practiced in a chemical reactor that includes a housing having: a shaft central axis in a fixed orientation in the housing; a housing inlet; a housing outlet; and an annular housing channel defining a unidirectional axial flow path for the process fluid from the housing inlet to the housing outlet. An axially impelling impeller is located in the annular housing passage and is rotationally driven about an impeller rotational axis coincident with the shaft central axis. A static annular diffuser is located within the annular housing passage and has a first axial end facing the impeller and a second axial end facing the housing outlet. The static annular diffuser defines a diffuser passage having a cross-sectional area that locally increases from a first axial end to a second axial end. When practicing the method, a hydrocarbon containing process fluid is introduced into the housing inlet. The impeller is rotationally driven by a shaft rotational power source, shifting the velocity of the process fluid tangentially relative to the shaft center axis from a first tangential direction at a leading edge of the axial end of the impeller to an opposite tangential direction at a trailing edge of the axial end of the impeller. The rotation of the impeller imparts energy into the process fluid, thereby accelerating the fluid to velocities greater than mach 1. The process fluid is discharged from the impeller through a diffuser channel of the static annular diffuser, decelerating the process fluid flowing through the diffuser channel to a velocity less than mach 1, and generating a shockwave in the process fluid within the diffuser channel. This raises the temperature of the process fluid downstream of the shock wave and cracks hydrocarbons in the process fluid.

The respective features of the exemplary embodiments of the invention described herein may be employed collectively or individually in any combination or sub-combination.

Drawings

Exemplary embodiments of the invention are further described in the following detailed description in conjunction with the drawings, in which:

FIG. 1 is an axial cross-sectional view of a single stage chemical reactor constructed in accordance with an embodiment of the invention, and a corresponding schematic view of the superposition of process fluids through the reactor;

FIG. 2 is a perspective view of the chemical reactor of FIG. 1 having a wall of an annular housing passage shown in cross-section;

3-4 are respective perspective and cross-sectional views of an embodiment of an uncovered impeller constructed in accordance with an embodiment of the invention;

FIG. 5 is a cross-sectional view of a covered impeller constructed in accordance with an embodiment of the invention;

FIG. 6 is an axial cross-sectional view of a single stage, double impeller chemical reactor constructed in accordance with an embodiment of the invention, and a corresponding schematic view of the superposition of process fluids through the reactor;

FIG. 7 is a two-stage chemical reactor constructed in accordance with an exemplary embodiment of the invention; and the number of the first and second groups,

fig. 8A and 8B are schematic diagrams of process fluid flow through a pair of turbine-type chemical reactors, and calculated static pressure and static temperature flow conditions of hydrocarbon-containing process fluid at various locations along axial flow path F through an exemplary chemical reactor having respective first and second stages constructed in accordance with the embodiment of fig. 6.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The figures are not drawn to scale.

Detailed Description

Embodiments of the present exemplary method and apparatus crack or crack hydrocarbons in a process fluid, such as hydrocarbons entrained in steam. The chemical reactor and method described in detail herein cracks hydrocarbons in a turbomachinery chemical reactor by: the process fluid is accelerated to a velocity greater than mach 1 using an axially impelling impeller and a shock wave is generated in the process fluid by decelerating the process fluid in a static diffuser having diverging diffuser passages. In some embodiments, the static pressure of the process fluid remains relatively constant (e.g., within plus or minus ten percent) as the process fluid passes through the impeller, but rises downstream of the shock wave. The temperature increase of the process fluid downstream of the shock wave cracks hydrocarbons entrained in the unidirectional flow path within a single pass without the need to recycle the process fluid to pass through the same stage another time. In some embodiments, the temperature increase by a single stage is greater than ten percent. Thus, in some embodiments, the process fluid passes through a single stage in 10 milliseconds or less, as compared to hundreds of milliseconds in known pyrolysis-type reactors. Faster mass flow rates in the chemical reactor of the present invention increase throughput. Unlike known pyrolysis-type reactors, no external heat is applied to the process fluid in the chemical reactor of the present invention to initiate or maintain the cracking chemical reaction. Eliminating the external heat required to operate the presently described turbomachinery chemical reactor as required in pyrolysis type reactors reduces energy consumption.

In some embodiments, a turbomachinery chemical reactor, or a continuous train of such reactors, has one or more axially-impelling impellers of multiple successive stages paired with diverging channels of a static diffuser. Successive stages crack additional hydrocarbons by successively increasing the temperature of the flowing process fluid. In some embodiments, the respective plurality of stages share a common housing, or in separate consecutive housings, or they are in a combination of separate and common housings in a common feed line. In some embodiments, one or more stages in the first reactor serve as a preheater for the process fluid before the process fluid flows into the downstream reactor. In some embodiments, the quench zone is incorporated into the chemical reactor downstream of the impeller. Some embodiments of the quench zone introduce a coolant fluid into the process fluid to stabilize the temperature of the process fluid. Other quench zones introduce an anti-fouling fluid into the process fluid to inhibit fouling in the diffuser passages. Still other quench zones introduce both the coolant fluid and the anti-fouling fluid into the process fluid.

Fig. 1 and 2 show a chemical reactor 10 for cracking hydrocarbons in a process fluid. The chemical reactor 10 is a turbine type chemical reactor comprising a housing 20 having a housing inlet 22, a housing outlet 24. The housing inlet 22 has a radial orientation, but in other embodiments the housing inlet 22 has an axial configuration. The housing outlet 24 has an axial orientation, but in other embodiments the housing outlet 24 has a radial configuration. In the chemical reactors disclosed herein, any combination of radial or axial inlets and outlets for inflow or outflow of the respective process fluids is used.

The housing 20 defines an annular housing passage 26 within the circumferential confines of a shroud wall 28. The housing passage 26 defines a unidirectional axial flow path F from the housing inlet 22 to the housing outlet 24 for containing the process fluid flowing through the axial flow path and cracking hydrocarbons in the process fluid. The flow diagram showing the axial flow path F is superimposed on the block diagram of the chemical reactor 10. At any point along the axial flow path F, the process fluid does not reverse the direction of flow from the inlet 22 toward the outlet 24.

A rotating shaft 30 located in the housing 20 is surrounded by the annular housing channel 26. The rotating shaft 30 is coupled to a shaft rotating power source or driver 32 and is rotatably driven in a direction R by the shaft rotating power source or driver 32, such as an electric motor, a steam or gas turbine, or other combustion type engine 32. The rotating shaft 30 defines a shaft center axis 34, the shaft center axis 34 being in a fixed orientation within the housing 20 and coincident with the axis of rotation of the rotating shaft 30.

An uncovered axial impeller 40 is mounted about the axis of rotation 30 in the annular housing passage 26 and is in fluid communication with the process fluid flowing between the inlet 22 and the outlet 24 of the housing 20. The impeller 40 has an impeller hub 42, the impeller hub 42 having an axial length extending axially along the shaft center axis 34 of the rotary shaft 30. A row of a plurality of impeller blades 50 project outwardly from the impeller hub 42, each of the impeller blades 50 having a leading edge 52 facing the housing inlet 22, and a trailing edge 54 facing the housing outlet 24. Each impeller blade 50 has a blade tip 56 at the distal end of the impeller hub 42 in opposed spaced relation to the shroud wall 28 of the annular housing passage 26, and opposed concave and

convex blade sidewalls

58, 60 between the blade tip, the leading edge 52 and the trailing edge 54. Each of the respective impeller blades 50 of the impeller 40 is configured to transition the velocity of the process fluid tangentially relative to the shaft center axis 34 from a first tangential direction 62 at the blade leading edge 52 to an opposite tangential direction 64 at the blade trailing edge 54 as the rotary shaft 30 rotates, and impart energy into the process fluid to discharge the process fluid from the trailing edges 54 of the impeller blades at a velocity greater than mach 1. For convenience, line 34A is drawn parallel to shaft central axis 34. In other embodiments, the axially-advancing impeller is a covered impeller having a circumferential shroud coupled to distal tips of impeller blades.

A static annular diffuser 70 located in the annular housing passage 26 is oriented between the axially advancing impeller 40 and the outlet 24 of the housing 20. The static annular diffuser 70 has a plurality of radially oriented circumferentially spaced diffuser passages 72 spanning a row of the annular housing passage 26. Each diffuser passage 72 has a first axial end 74 facing the axially-propelling impeller 40, and a second axial end 76 facing the housing outlet 24. In the embodiment of fig. 1 and 2, the diffuser passage 72 is defined by opposing pairs of spiral diffuser vanes 78. Each blade has a pair of opposing

sidewalls

80 and 82 circumferentially separated by a hub wall 84. The configuration of the particular blade 78 of fig. 1 and 2 is a side plate having a uniform wall thickness between opposing

side walls

80 and 82. In other embodiments, the blades have various thicknesses, such as airfoils. The local cross-section of each diffuser passage 72 increases from its first axial end 74 to its second axial end 76. Specifically, the local cross-sectional height T of the vane passage 72_HDefined between the hub wall 84 and the shroud wall 28 of the housing annular passage 26. Local cross-sectional width T_WDefined between respective

opposite sidewalls

80 and 82 between the two opposite blades 78. The local cross-sectional area of each vane diffuser passage increases through a local cross-sectional height T_HAnd/or local cross-sectional width T_WThe increase in (c) is achieved. The diffuser passage 72 is configured to decelerate the process fluid discharged from the impeller blades 50 in the diffuser passage 72 to a velocity less than Mach 1, thereby generating a shock wave in the process fluid and increasing the temperature of the process fluid downstream of the shock wave.

The chemical reactor 10 has a plurality of circumferentially spaced turning vanes 92 oriented in the annular housing passage 26 between the static annular diffuser 70 and the outlet 24 of the housing 20. Each diverter vane 92 has a leading edge 94 facing the static annular diffuser 70 and a trailing edge 96 facing the outlet 24 of the housing 20. The opposed pairs of diverter blades 92 define a height T therebetween having a local variation_HAnd width T_WTo the throat 98 of the diverter blade. The partial cross-section of each turning vane throat decreases from its respective pair of opposing turning vane leading edges 94 to its respective pair of opposing turning vane trailing edges 96 before discharge from the outlet 24 of the housing, or before the inlet of a downstream stage of the same chemical reactor 10, or before another separate and discrete chemical reactor 10. As shown in fig. 1, the outlet 24 is defined as an annular passage between the exhaust cone 100 and the outlet transition 102. An optional process fluid quench zone 104 is oriented axially downstream of the impeller 40, the process fluid quench zone 104 having a discharge nozzle 106, the discharge nozzle 106 for introducing a coolant fluid into the process fluid to stabilize the temperature of the process fluid. In other embodiments, the discharge nozzle 106 introduces an anti-fouling fluid into the process fluid to inhibit fouling from occurring within the diffuser passage 72 or within any component structure downstream of the diffuser passage. In other embodiments, one or more quench regions are oriented at other locations downstream of the impeller 40, such as in an annular space between the exhaust cone 100 and the outlet transition 102.

The axially-advancing wheels and other components of the turbine-type chemical reactors described herein are manufactured by known manufacturing methods, such as by joining the hub and blades of the sub-components, whether from one or more of forgings, castings, additive manufacturing, or fixings. The exemplary uncovered embodiment of the axially advancing impeller 120 of fig. 3 and 4 has an integral impeller hub 122 and impeller blades 124 formed by casting, forging, additive manufacturing, or forming/cutting a billet of the billet. The covered integral axial propulsion impeller 126 embodiment of fig. 5 has a hub 127, blades 128 and a circumferential shroud 129 at the distal tips of the blades.

In some embodiments, at least two or more chemical reactors with successive axially-impelling impellers 40 and shock-wave-inducing static toroidal diffusers 70 of the type shown in fig. 1 and 2 are coupled in series in stages. So configured, the process fluid discharged through the static diffuser 70 of one reactor 10 is in fluid communication with the axially-propelling impeller 40 of the other reactor. In these multiple stage embodiments, the respective reactors 10 are located in separate respective housings 20 or in a shared common housing.

The chemical reactor 110 of fig. 6 has a pair of axially spaced first and second

axial impelling impellers

40A, 40B mounted together about the axis of rotation 30. The structure of the individual components in chemical reactor 110 are similar to the structure of the individual components of chemical reactor 10 of fig. 1 and 2, unless otherwise specified. The trailing edges 54 of the blades 50 of the first impeller 40A face the leading edges 52 of the blades 50 of the second impeller 40B. A rotating scoop 112 is interposed between the first axial impeller 40A and the second axial impeller 40B. The rotor 112 has a row of fixed rotor blades 114 in the annular housing passage 26 for aligning the process fluid discharged from the trailing edges 54 of the blades 50 of the first impeller 40A parallel to the leading edges 52 of the blades 50 of the second impeller 40B.

The two-stage turbine-type chemical reactor 210 of fig. 7 includes a first stage axial impeller 240A and a first stage static annular diffuser 270A located downstream of the housing inlet 222. The second stage in sequence includes an axial impeller 240B and a static annular diffuser 270B. Both of the first and second stages are oriented with a shared common housing 220. In other embodiments, the first stage and the second stage are located in separate housings. The process fluid quench zone 300 is in communication with the exhaust outlet 224 axially downstream of the impeller 240B. The nozzle 302 introduces a coolant fluid into the process fluid to stabilize the temperature of the process fluid. In other embodiments, the nozzle 302 introduces an anti-fouling fluid into the process fluid to inhibit fouling within chemical plant components downstream of and subsequently in contact with the process fluid.

In other embodiments, a turbine incorporating a pair of axially-impelling impellers of the type used in the turbine-

type chemical reactor

10, 110 or 210 and a static annular diffuser is used to preheat the process fluid prior to introduction into the downstream turbine-type chemical reactor which generates a sufficient temperature increase to crack hydrocarbons in the process fluid. The preheater includes: a preheated impeller similar to impeller 40 of figure 1 for accelerating the process fluid to a velocity greater than mach 1; and a preheated static annular diffuser, similar to diffuser 70 of figure 1, for decelerating the process fluid flowing therethrough to a velocity less than mach 1, thereby generating a shockwave in the process fluid within the passages of those diffusers and increasing the temperature of the process fluid downstream of the shockwave.

Fig. 8A and 8B, taken together, are a schematic representation of a process fluid flowing through a pair of turbine-

type chemical reactors

110A, 110B, and a schematic representation of calculated static pressure and temperature flow conditions of the hydrocarbon-containing process fluid at various locations along the axial flow path F. The exemplary chemical reactor has respective first and

second stages

110A, 110B constructed in accordance with the embodiment of fig. 6. As previously described, the components of the reactor 110 of fig. 6 are substantially similar to the corresponding components of the reactor 10 of fig. 1 and 2. Thus, names or components will be used interchangeably in all those figures.

The

reactors

110A and 110B of fig. 8A and 8B are shown in separate

respective housings

20A and 20B, but in other embodiments, the

reactors

110A and 110B share a common housing. In some embodiments, the reactor has more than two stages. One or more of the initial stages of other reactor embodiments is a preheater for heating the process fluid to a temperature below that required to initiate and/or sustain the cracking reaction. Then, in those embodiments, one or more subsequent downstream stages crack hydrocarbons. The particular static pressure and static temperature and the slope of the static pressure curve and static temperature curve vary with the particular heating rate and reaction rate of the different process fluid/hydrocarbon mixtures. Any process fluid/hydrocarbon mixture is expected to experience similar overall changes in temperature and pressure as it flows through the stages as shown in the base curves of fig. 8A and 8B.

Referring specifically to fig. 8A and generally to fig. 1, 2 and 6, a hydrocarbon containing process fluid is introduced into housing inlet 22/22a at a given temperature and pressure. In some embodiments, the process fluid is preheated by application of external heat in a heat exchanger, or by a shock wave induced in a turbine-type preheater having a pair of axially-impelling impellers and a static annular diffuser of the type described herein. The process fluid is accelerated by driving impeller 40A, the construction of impeller 40A being similar to impeller 40A of fig. 6 and impeller 40 of fig. 2. As shown in fig. 2, the rotating blades 50 of the impeller 40 transition the velocity of the process fluid tangentially relative to the shaft center axis 34 or its parallel axis 34A from a first tangential direction 62 at the leading edge axial end 52 of the impeller to an opposite tangential direction 64 at the trailing edge axial end 54 of the impeller. The impeller 40A of fig. 8A (as well as fig. 6) accelerates the process fluid without requiring a significant increase (i.e., a change of plus or minus ten percent) in static pressure or static temperature. The process fluid discharged from the trailing edges 54 of the blades 50 of the impeller 40A is directed through the diverter blades 114 of the rotating bucket 112 to align the flow direction of the process fluid with the leading edges 52 of the blades 50 of the impeller 40B. The impeller 40B in turn accelerates the process fluid to a higher velocity-above mach 1-than the process fluid in the impeller 40A. The process fluid is discharged from the trailing edges 54 of the blades 50 of the impeller 40B without requiring a significant increase in static pressure or static temperature (i.e., a change of plus or minus ten percent). As shown in fig. 8A, the process fluid pressure and temperature profile is relatively flat from the inlet 22A up to the discharge from the second impeller 40B.

The process fluid discharged from the second impeller 40B enters the static annular diffuser 70A at the first axial end 74A. The locally increased cross-sectional area of the diffuser passage 72 (see, e.g., fig. 1 and 2) decelerates the process fluid to velocities less than mach 1, resulting in a significant reduction in both static temperature and static pressure. This deceleration induces a shock wave 90A in the diffuser passage 72 somewhere along the axial length of the static diffuser 70A. The axial position of the shockwave 90A varies with the characteristics of the process fluid/entrained hydrocarbons, the backpressure in the static diffuser 70A and/or in the axial flow path F downstream of the static diffuser 70A, the geometry of the diffuser passage 72 and/or the turning vanes 92 and/or the housing outlet 24A (e.g., the locally varying cross-section of any of the above), and other factors. The shock wave 90A induces a downstream temperature increase sufficient to crack hydrocarbons in the process fluid. In some embodiments, the shock wave 90A increases the absolute temperature of the process fluid from the inlet 22A of the housing to downstream of the shock wave by at least ten percent (10%) within ten milliseconds (10MS) without changing the static pressure by more than plus or minus ten percent (10%). In some embodiments, the cracking reaction continues at least partially through the diverter vane 92A and the outlet 24A, resulting in an increase in the temperature of the process fluid, as indicated by the arrowed line segment ending at reference numeral 8B. The process fluid exits the housing outlet 24A for further processing by the second stage reactor 110B.

Referring to fig. 8B and also referring generally to fig. 1, 2, and 6, process fluid (labeled 8A) exiting from the shell outlet 24A of the reactor 110A is introduced into the shell inlet 22B. Since the process fluid downstream of the shock wave 90A absorbs heat, the temperature of the process fluid entering the shell inlet 22B is typically lower than the temperature of the process fluid immediately downstream of the shock wave in order to sustain the cracking reaction. The process fluid is again accelerated in the reactor 110B to a velocity greater than mach 1 by passing successively through the impeller 40A, the rotating scoop 112, and the impeller 40B while the corresponding static pressures and static temperatures remain relatively stable (i.e., plus or minus ten percent).

Again, while in the reactor 110A, the process fluid discharged from the second impeller 40B of the reactor 110B enters the static annular diffuser 70B at the first axial end 74B. The locally increased cross-sectional area of the diffuser passage 72 (see, e.g., fig. 1 and 2) decelerates the process fluid to velocities less than mach 1, resulting in a significant reduction in both static temperature and static pressure. The deceleration isA shock wave 90B is induced in the diffuser passage 72 somewhere along the axial length of the static diffuser 70B. The axial position of the shockwave 90B within the static diffuser 70B varies with the characteristics of the process fluid/entrained hydrocarbons, the backpressure in the static diffuser 70B and/or in the axial flow path F downstream of the static diffuser 70B, the geometry of the diffuser passage 72 and/or the turning vanes 92B and/or the housing outlet 24B (e.g., the locally varying cross-section of any of the above), and other factors. The shock wave 90B induces a downstream temperature increase sufficient to crack hydrocarbons in the process fluid. In some embodiments, the shock wave 90B increases the absolute temperature of the process fluid from the inlet 22B of the housing to downstream of the shock wave by at least ten percent (10%) within ten milliseconds (10MS) without changing the static pressure by more than plus or minus ten percent (10%). In some embodiments, the cracking reaction continues at least partially through the diverter vane 92B and the outlet 24B, resulting in a temperature increase in the process fluid, as by terminating at reference F_OUTIndicated by the arrowed line segment at (a). In some embodiments, the diverter blades restrict the flow cross-sectional area of the process fluid. Process fluid F_OUTExits the housing outlet 24B for further processing. In some embodiments, a quench zone 104 is incorporated in the second stage reactor 110B downstream of the second impeller 40B to control the cracking reaction rate through injection of cooling steam or other coolant fluid and/or anti-fouling fluid. In some embodiments, the quench zone 104 terminates further cracking reactions. In some embodiments, a quench exchanger, such as quench exchanger 300 of fig. 7, is in fluid communication with shell outlet 24B.

Embodiments of the turbine-type chemical reactor disclosed herein facilitate cracking of hydrocarbons entrained in a process fluid without the need for the application of external heat as required by pyrolysis-type chemical reactors. The presently disclosed reactor ensures higher mass flow rates and faster cracking reaction times than known pyrolysis-type chemical reactors with its unidirectional axial flow path through the annular shell channel. Fewer of the presently disclosed chemical reactors are required to process the desired output rate of cracked hydrocarbons as compared to known pyrolysis-type chemical reactors; this reduces plant construction and maintenance costs.

Although various embodiments which incorporate the present invention have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate the claimed invention. The invention is not limited in its application to the details of the exemplary embodiments of construction and the arrangement of components set forth in the description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are to be construed broadly; including direct or indirect mounting, connecting, supporting, and coupling. Further, "connected" and "coupled" are not restricted to physical, mechanical, or electrical connections or couplings.

Claims

1. A chemical reactor (10) for cracking hydrocarbons in a process fluid, the chemical reactor (10) comprising:

a housing (20), the housing (20) having a housing inlet (22), a housing outlet (24), and an annular housing passage (26), the annular housing passage (26) defining a unidirectional axial flow path from the housing inlet to the housing outlet for containing a process fluid and cracking hydrocarbons in the process fluid in the axial flow path;

a rotating shaft (30) located in the housing and surrounded by the annular housing channel and for coupling to a shaft rotational power source (32), the rotating shaft defining a shaft central axis (34), the shaft central axis (34) being in a fixed orientation in the housing and coincident with a rotational axis of the rotating shaft;

an axial impeller (40), said axial impeller (40) mounted about said axis of rotation within said annular housing channel, and is in fluid communication with a process fluid flowing between the housing inlet and the housing outlet, the impeller including an impeller hub having an axial length extending axially along the shaft center axis of the rotary shaft, a row of a plurality of impeller blades (50) projecting outwardly from the impeller hub, each of the impeller blades having a leading edge (52) facing the housing inlet, a trailing edge (54) facing the housing outlet, a blade tip (56) at a distal end of the impeller hub in opposed spaced relation to the annular housing channel, and opposed concave (58) and convex (60) blade sidewalls between the blade tip and the leading and trailing edges of the impeller blade, respectively; the impeller blades are configured to transition the velocity of the process fluid from a first tangential direction (62) at the leading edges of the blades to an opposite tangential direction (64) at the trailing edges of the blades tangentially relative to the shaft center axis as the rotating shaft rotates, and impart energy into the process fluid to discharge the process fluid from the respective trailing edges of the impeller blades at a velocity greater than Mach 1; and the number of the first and second groups,

a static annular diffuser (70) located in the annular housing passage and oriented between the axial impeller and the housing outlet, the static annular diffuser having a plurality of radially oriented circumferentially spaced diffuser passages (72) spanning a row of the annular housing passage; each of the diffuser passages has a first axial end (74) facing the axially-propelling impeller and a second axial end (76) facing the housing outlet, the partial cross-section of each diffuser passage increasing from the first axial end of each diffuser passage to the second axial end of each diffuser passage; the diffuser passage is configured to decelerate a process fluid discharged from the impeller blades in the diffuser passage to a velocity less than Mach 1, thereby generating a shockwave (90) in the process fluid and increasing a temperature of the process fluid downstream of the shockwave prior to discharging the process fluid from the housing outlet.

2. The chemical reactor of claim 1, the respective circumferentially spaced diffuser passages being defined between a shroud wall (28) of the annular housing passage (26) and a helical diffuser vane (78) having opposite radially outwardly directed vane side walls (80, 82) separated by a hub wall (84); a partial cross-section of the respective diffuser passage is defined by a vane throat width between opposing adjacent vanes and a vane throat height from the hub wall to the shroud wall of the annular housing passage, either or both of the respective diffuser passage throat width and/or diffuser passage throat height increasing from the first axial end (74) to the second axial end (76) of the diffuser passage.

3. The chemical reactor of claim 1 further comprising circumferentially spaced turning vanes (92) in the annular housing channel (26), the turning vanes (92) oriented between the static annular diffuser (70) and the outlet (24) of the housing, the respective turning vanes having a leading edge (94) facing the static annular diffuser and a trailing edge (96) facing the housing outlet, opposing pairs of turning vanes defining a turning vane throat (98) therebetween, a local cross-section of each turning vane throat decreasing from a respective pair of opposing turning vane leading edges of each turning vane throat to a respective pair of opposing turning vane trailing edges of each turning vane throat.

4. The chemical reactor of claim 1, further comprising a process fluid quench zone (104) axially downstream of the impeller for introducing a coolant fluid (106) into the process fluid to stabilize a temperature of the process fluid; or for introducing an anti-fouling fluid into the process fluid to inhibit fouling within the diffuser passages.

5. The chemical reactor of claim 1, at least two of said chemical reactors (210) being serially coupled, wherein process fluid discharged through the static diffuser (270B) of one reactor is in fluid communication with the axially-impelling impeller (240B) of the other reactor, wherein the respective reactors are located in separate respective housings or in a shared common housing (220).

6. The chemical reactor (110) of claim 1, further comprising:

a pair of axially spaced first (40A) and second (40B) axially impelling impellers mounted together about the axis of rotation (30), wherein the trailing edge (54) of the first impeller faces the leading edge (52) of the second impeller;

a row of stationary bucket blades (114) interposed in the annular housing channel (26) between the first and second axially impelling impellers for aligning a flow of process fluid discharged from a trailing edge of the first impeller parallel to a leading edge of the second impeller.

7. Chemical reactor according to claim 6, at least two of said chemical reactors (110A, 110B) being serially coupled, wherein a process fluid discharged through the static diffuser (70A) of one reactor (110A) is in fluid communication with the first axial propelling impeller (40A) of the other reactor (110B), wherein the respective reactors are located in separate respective housings or in a shared common housing.

8. The chemical reactor of claim 1, the axially-propelling impeller (120) comprising an integral impeller hub (122) and impeller blades (124).

9. The chemical reactor (110B) of claim 1, further comprising a process fluid preheater (110A) coupled to the shell inlet (22A) for preheating a process fluid prior to introduction into the reactor (110B); the process fluid preheater comprises: a preheated impeller (40A) for accelerating the process fluid to a velocity greater than Mach 1; and a pre-heating static toroidal diffuser (70A), said pre-heating static toroidal diffuser (70A) for decelerating the process fluid flowing through said pre-heating static toroidal diffuser to a velocity less than mach 1, thereby generating a shockwave (90A) in the process fluid within those diffuser channels and increasing the temperature of the process fluid downstream of said shockwave.

10. A method for cracking hydrocarbons in a process fluid, comprising:

providing a chemical reactor (10), the chemical reactor (10) having:

a housing (20), the housing (20) having a shaft center axis (34) in a fixed orientation in the housing, a housing inlet (22), a housing outlet (24), and an annular housing passage (26) defining a unidirectional axial flow path for the process fluid from the housing inlet to the housing outlet;

an axially impelling impeller (40), said axially impelling impeller (40) being located within said annular housing passage and being rotationally driven about an impeller axis of rotation coincident with said shaft central axis;

a static annular diffuser (70), said static annular diffuser (70) located within said annular housing channel, said static annular diffuser (70) having a first axial end (74) facing said axially-propelling impeller and a second axial end (76) facing said housing outlet, said static annular diffuser defining a diffuser channel (72), said diffuser channel (72) having a locally-increasing cross-sectional area from said first axial end to said second axial end of said static annular diffuser;

introducing a stream of a hydrocarbon-containing process fluid into the housing inlet;

rotationally driving the impeller with a shaft rotational power source (32), shifting the velocity of the process fluid tangentially relative to the shaft central axis from a first tangential direction (62) at a leading edge (52) of an axial end of the impeller to an opposite tangential direction (64) at a trailing edge (54) of the axial end of the impeller, and imparting energy into the process fluid, thereby accelerating the process fluid to a velocity greater than mach 1;

discharging the process fluid from the impeller through the diffuser channel of the static annular diffuser, decelerating the process fluid flowing through the diffuser channel to a velocity less than mach 1, generating a shockwave (90) in the process fluid within the diffuser channel, increasing the temperature of the process fluid downstream of the shockwave, and cracking hydrocarbons in the process fluid.

11. The method of claim 10, further comprising quenching (104) the process fluid with a coolant fluid (106) axially downstream of the impeller (40) to stabilize a temperature of the process fluid; or with an anti-fouling fluid to inhibit fouling in the diffuser passages (72).

12. The method of claim 10, further comprising restricting a flow cross-sectional area of the process fluid axially downstream of the static annular diffuser (70) with turning vanes (92).

13. The method of claim 10, further comprising serially coupling at least two of the chemical reactors (110A, 110B), conveying process fluid discharged through the static diffuser (70A) of one reactor (110A) to the axially-impelling impeller (40A) of the other reactor (110B), wherein the respective reactors are located in separate respective housings (20) or in a shared common housing (220).

14. The method of claim 10, further comprising preheating the process fluid prior to introducing the process fluid into the shell inlet of the chemical reactor (110B) by:

accelerating the process fluid to a velocity greater than mach 1 using a preheated impeller (40A); and the number of the first and second groups,

discharging the process fluid from the pre-heated impeller through diffuser channels (72) of a pre-heated static annular diffuser (70A), decelerating the process fluid flowing through the diffuser channels to a velocity less than mach 1, generating a shockwave (90A) in the process fluid within those diffuser channels, increasing the temperature of the process fluid downstream of the shockwave.

15. The method of claim 10, further comprising disposing a chemical reactor (210) having a plurality of successive stages of driven axially-impelling impellers (240A, 240B) within the annular casing passage between the casing inlet and the static annular diffuser (270B), the axially-impelling impellers of each of the successive stages accelerating the process fluid to a higher velocity.

16. The method of claim 15, further comprising driving a pair of axially spaced first (40A) and second (40B) axially impelling impellers mounted together about said axis of rotation (30), wherein trailing edges (54) of the blades (50) of said first impeller (40A) face leading edges (52) of the blades (50) of said second impeller (40B); and the number of the first and second groups,

the process fluid discharged from the trailing edges of the blades of the first impeller is aligned parallel to the leading edges of the blades of the second impeller by interposing a row of fixed rotor blades (114) in the annular housing passage (26) between the first and second axially propelling impellers.

17. The method of claim 10, further comprising varying the location of the shockwave (90) generated in the process fluid within the diffuser passage (72) by modifying one or more of a cross section of the housing outlet (24) and/or a restriction of process fluid flow downstream of the static annular diffuser (70) and/or a backpressure within the static annular diffuser.

18. The method of claim 10 further comprising increasing the absolute temperature of the process fluid from the inlet (22) of the housing (20) downstream of the shock wave (90) by at least ten percent (10%) within ten milliseconds (10MS) without changing static pressure by more than plus or minus ten percent (10%).